1. Field of the Invention
This invention relates to a closed circuit television apparatus suitable for a supervisory system.
2. Description of the Prior Art
Generally, as a supervisory system for observation of different locations from a central supervisory station, a closed circuit television apparatus is employed. At each location to be observed, a television camera is used, and at the central supervisory station, a monitor for receiving video signals transmitted from the selected television cameras and a switching device for selectively connecting the television cameras to the monitor are located.
In this type of supervisory system, the attendant must identify the television camera transmitting the video signals corresponding to the image being reproduced on the monitor. For this purpose, in the conventional supervisory system the attendant identifies the television camera by the connection condition of the switching device, but the attendant may occasionally misconceive such connection condition.
Another conventional system, superpose characters on the reproduced image on the monitor. The conventional system however is limited to few characters, furthermore these characters cannot be switched off, removed or having their position shifted from the reproduced image on the receiver or monitor at the monitoring station. The conventional system, therefore, is disadvantaged by the character superpose on top of important object to be surveyed so that said character interrupts the identification of an important portion in the image on the monitor.